Author(s): Yasuhiro Yoshikawa; Yasuharu Watanabe; Hiroshi Hayakawa; Yasuyuki Hirai
Linked Author(s): Yasuharu Watanabe
Keywords: No Keywords
Abstract: This study aimed to clarify the situation of a river ice jam generated on a river located in eastern Hokkaido in February, 2010. We carried out water level observation, water temperature, video photography and aerial photography, and also visually monitored the river ice area. The results served to elucidate the conditions of the ice jam's generation. First, higher temperatures caused snow to melt, leading to increased discharge and higher water levels. As a result of this water level rise, river ice was lifted and broke up before flowing downstream and stopping at a narrow point in the river. The ice build-up resulted in further narrowing of the discharge area, causing the water level to rise rapidly. The composite n-value seen during the period of the river ice jam was estimated to be in the range from 0.034 to 0.058 based on analysis of observation data. The relationships linking the flow velocity coefficient and the radius and energy gradient in river ice jam conditions was also clarified.
Year: 2012